TRENTON, N.J. -- Using birth-control pills or other contraceptives to block periods is gaining popularity, particularly among young women, doctors say.

"I have a ton of young girls in college who are doing this," said Dr. Mindy Wiser-Estin, a gynecologist in Little Silver. "There's no reason you need a period."

Stephanie Sardinha, 22, hasn't had a period since she was 17. A college student in Lisbon Falls, Maine, Sardinha uses NuvaRing, a vaginal contraceptive ring. After the hormones run out in three weeks, she replaces the ring right away instead of following instructions to leave it out for a week to allow menstruation.

Such medical jury-rigging soon will be unnecessary. Already, the Seasonale birth-control pill limits periods to four a year. The first continuous-use birth-control pill, Lybrel, likely will soon be on the U.S. market, and drug companies are lining up other ways to limit or eliminate the period.

Sardinha says elimination of her periods has been great for her marriage, preventing monthly crankiness and improving her sex life.

"I would never go back," said Sardinha, who got the idea from her aunt, a nurse practitioner.

Most doctors say they don't think suppressing menstruation is riskier than regular long-term birth-control use, and one survey found a majority have prescribed contraception to prevent periods. Women have been using the pill for nearly half a century without significant problems, but some doctors want more research on long-term use.

Findings in surveys

The new methods should be popular among menstruating women. A non-scientific Web survey for the Association of Reproductive Health Professionals found at least two-thirds of the respondents are bothered by fatigue, heavy bleeding, "really bad cramps" and even anger. Nearly half said they would like to have no period at all or decide when to have one.

Two recent national surveys found about 1 in 5 women have used oral contraceptives to stop or skip their period.

"If you're choosing contraception, then there's not a lot of point to having periods," said Dr. Leslie Miller, a University of Washington-Seattle researcher and associate professor of obstetrics and gynecology whose Web site, www.noperiod.com, explains the option. She points out that women on hormonal contraception don't have real periods anyway, just withdrawal bleeding during the break from the hormone progestin.

According to Miller, modern women endure up to nine times more periods than their great-grandmothers, who began menstruating later, married young and naturally suppressed periods for years while they were pregnant or breast-feeding. Today's women may have about 450 periods.

The period is "way over-romanticized," says Linda Gordon, a New York University professor specializing in women's history and the history of sexuality.

"It doesn't take long for women to go from being excited about having a period to feeling it's a pain in the neck," said Gordon, author of "The Moral Property of Women: A History of Birth Control Politics in America."

She says caution is needed because there's not enough data on long-term consequences of using hormones continuously. Gordon notes that menopausal women for years were told that hormone drugs would keep them young--until research uncovered unexpected risks.

"People should proceed very cautiously," she said.

Less hormone

Today's birth-control pills contain far less estrogen and progestin than those two generations ago but still increase the risk of heart attack, stroke and blood clots. Doctors say the pill should not be used by women who have had those conditions, unexplained vaginal bleeding or certain cancers, or if they are smokers older than 35.

But there are reported benefits from taking oral contraceptives too, such as a lower risk of ovarian and endometrial cancer, osteoporosis and pelvic inflammatory disease. And forgoing periods means no premenstrual syndrome and a lower risk of anemia and migraines, says Dr. Sheldon Segal, co-author of "Is Menstruation Obsolete?" Segal has been involved in research for several contraceptives.

Almost since the first pill arrived in 1960, women have manipulated birth control to skip periods for events such as a wedding, vacation or sports competition.

Female doctors and nurses were among the first to block menstruation long term to suit their schedules, said Susan Wysocki, head of the National Association of Nurse Practitioners in Women's Health.

"They were then more comfortable recommending it to their patients," said Wysocki, who uses a vaginal ring to prevent menstruation.

The idea gained momentum after Barr Pharmaceuticals launched Seasonale in November 2003. It's a standard birth-control pill taken for 12 weeks, with a break for withdrawal bleeding every three months. Amid wide acceptance by doctors, sales shot up 62 percent last year, to $110 million.

Publicity for Seasonale made women wonder, if just four periods a year are OK, why have any at all?

"What Seasonale did is get rid of that nuisance," says Dr. Peter McGovern of University of Medicine and Dentistry of New Jersey.

New extended-cycle contraceptives will do the same. Wyeth is hoping by late next month to get Food and Drug Administration approval to sell Lybrel, its low-dose, continuous birth-control pill; approval also is pending in Canada and Europe.

On FDA approval roster

Also next month, the FDA should decide whether to approve Implanon, a single-rod, three-year contraceptive implanted in the upper arm that maker Organon USA has been selling in Europe for a decade.

Barr, aiming to be a leader in extended contraception, last November bought the maker of ParaGard, an intrauterine device that blocks periods in some women. Barr's new product Seasonique, a successor to Seasonale, is awaiting federal approval.

Dr. Patricia Sulak, who researches extended contraception at Texas A&M College of Medicine, applauds this new trend. The doses in standard pills are now so low, she said, that having seven days off them raises the risk of pregnancy.

"This redesign is way overdue," she said. "[/SIZE][/FONT]It's going to be the demise of 21-7."